1. Field of the Invention
The present invention relates to a cooling structure for a street lamp using light emitting diodes (hereinafter, also referred to simply as an ‘LED street lamp’), and more specifically to a cooling structure for an LED street lamp whose air-cooling efficiency is markedly improved to achieve high energy efficiency as well as prolonged service life of the LED street lamp.
2. Description of the Related Art
Generally, sodium and mercury light bulbs are widely used in street lamps. Sodium and mercury light bulbs are available in suitable applications based on their inherent advantages and disadvantages. Since light from the conventional light bulbs shows a strong tendency to scatter in all directions, low luminance is inevitable on the ground where light is needed and relatively high power consumption is required, resulting in low energy efficiency.
Under such circumstances, LED street lamps have been developed in recent years. LED street lamps require considerably low power consumption compared to sodium and mercury street lamps and exhibit brightness comparable or superior to conventional street lamps. In addition, the service life of LED street lamps is several times longer than that of sodium and mercury street lamps, resulting in a remarkable reduction in management expense. Based on these advantages, LED street lamps have become increasingly used and are replacing conventional street lamps.
Light emitting diodes currently used in street lamps have the advantage of high luminance. Other advantages of LEDs are low power consumption and long service life when compared to conventional light bulbs. Based on these advantages, the use of LEDs is remarkably increasing in various industrial fields, such as indoor lighting, decorative lighting and automotive lighting systems.
A high level of luminance required in a street lamp cannot be met by the use of a single light emitting diode. In view of high luminance, street lamps are developed using a plurality of light emitting diodes. For example, a lighting lamp with high luminance is manufactured by connecting several to tens of light emitting diodes to one another to construct modules and connecting the modules in series or parallel.
However, when lighting systems comprising modules composed of a plurality of light emitting diodes are turned ‘on’ for a long time, the light emitting diodes with poor heat resistance are thermally damaged, leading to failure of the lighting systems. Accordingly, lighting systems using LEDs must necessarily be provided with cooling structures to dissipate heat generated from the LEDs. This heat dissipation protects the lighting systems from failure due to overheating. In view of these situations, LED street lamp manufacturers utilize inherent techniques of their own to dissipate heat generated from LEDs.
Numerous cooling structures for LED street lamps have been developed. In a typical cooling structure, light emitting diodes are installed on a partition board made of aluminum with excellent heat dissipation performance to dissipate heat generated during turn-on.
Since the light emitting diodes are directly attached to the aluminum partition board in the cooling structure, heat generated from the LEDs is conducted at a very low rate. In addition, the heat transferred from the LEDs is not rapidly dissipated in the partition board because no cooling means is provided in the partition board, leading to poor cooling efficiency of the cooling structure.